The slide in US stocks since the terrorist attacks earlier this month has wiped billions off the net worth of America's wealthiest businessmen.

According to Forbes magazine, which publishes an annual list of the richest citizens in the US, 50 of these people have lost more than $44bn (£30bn) in the aftermath of the attacks.

Amount lost since attacks on the US

Bill Gates (Microsoft) $7.2bn

Paul Allen (Microsoft) $4bn

Larry Ellison (Oracle) $3.4bn

Warren Buffett (Berkshire Hathaway) $2.8bn

Steve Ballmer (Microsoft) $2.5bn

Michael Dell (Dell Computers) $1.6bn

Source: Forbes

The biggest loser was Microsoft's Bill Gates, who has seen his personal wealth tumble by $7.2bn (£4.9bn).

The Forbes issue with its annual rich list was at the printers when the US was attacked on 11 September, so the editors compiled the new post-attack figures by way of balance.

"By looking at the impact of recent events on the working capital of a group of America's top businesspeople and
investors, we thought we could provide one measure of the
shock the American financial system sustained," said
Forbes editor Bill Baldwin.

Forbes calculated the losses by comparing how people's wealth had changed between 27 August and 24 September.

During that period the main US share index - the Dow Jones Industrial Average - dropped more than 17%.

Bill still on top

The slide in share values, which was already well under way before the attacks on the US, has wiped more than 20% off the wealth of the top 400 people according to Forbes.

Warren Buffett: up to number two

The combined net worth of those included fell from $1.2 trillion (£816bn) in 2000 to $946bn (£643bn) this year, only the third time the value has fallen since the magazine began compiling the list in 1982.

Despite losing more than $7bn over the past couple of weeks, Bill Gates still comfortably tops the Forbes list.

The veteran investor Warren Buffett moved up to second place, and third was the other Microsoft co-founder Paul Allen.

Oracle's chief executive Larry Ellison slipped from second place to fourth.

Richest Americans

1, Bill Gates$54bn

2, Warren Buffett $33.2bn

3, Paul Allen $28.2bn

4, Larry Ellison $21.9bn

Source: Forbes

In a further sign of the fall from grace of the technology sector, 54 so-called "new economy" entrepreneurs fell out of the top 400.

The average person on the list is worth about $2.4bn (£1.6bn), a $600m (£408m) fall on last year's figure.